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Weber M, Wolf JC, Haisch C. Effect of Dopants and Gas-Phase Composition on Ionization Behavior and Efficiency in Dielectric Barrier Discharge Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:538-549. [PMID: 36827232 DOI: 10.1021/jasms.2c00279] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Cold plasma-based ionization techniques allow for soft ionization of a wide variety of chemical compounds. In this chemical ionization mechanism, the atmosphere plays a crucial role in ionization. Knowing its influence is critical for the optimization of analysis conditions and interpretation of resulting spectra. This study uses soft ionization by chemical reaction in transfer (SICRIT), a variant of dielectric barrier discharge ionization (DBDI), that allows for a controlled atmosphere to investigate atmosphere and dopant effects. The influence of eight makeup gas compositions (dry nitrogen, room air, and nitrogen-enriched with either water, HCl, MeOH, hexane, NH3, and fluorobenzene) on the ionization with SICRIT was investigated. Fifteen compound classes, comprising alkanes, polyaromatic hydrocarbons (PAHs), terpenes, oxygen-containing terpenes, alkylphenols, chlorophenols, nitrophenols, trialkylamines, triazines, phthalates with or without ether groups, aldehydes, ketones, fatty acid methyl esters (FAMEs), and polyoxy-methylene ethers (OMEs) were measured via gas chromatography SICRIT high-resolution mass spectrometry (GC-SICRIT-HRMS). The different atmospheres were compared in terms of generated ions, ion intensities and fragmentation during ionization. Measurements of reactant ions were performed for a better understanding of the underlying mechanisms. All 15 compound classes were mostly softly ionized. For most compound classes and atmospheres, protonation is the dominant ionization mode. The highest number of compounds ionized via protonation was observed in dry nitrogen, followed by room air and humid nitrogen. The study should work as a guideline for the choice of atmosphere for specific compound classes and the interpretation of spectra generated under a specific atmosphere.
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Affiliation(s)
- Markus Weber
- Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, 85748 Garching, Germany
- Plasmion GmbH, 86167 Augsburg, Germany
| | | | - Christoph Haisch
- Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, 85748 Garching, Germany
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2
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Chen X, Newsome GA, Buchanan M, Glasper J, Hua L, Latif M, Gandhi V, Li X, Larriba-Andaluz C. Flow-Optimized Model for Gas Jet Desorption Sampling Mass Spectrometry. J Phys Chem A 2023; 127:1353-1359. [PMID: 36701191 DOI: 10.1021/acs.jpca.2c07999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Thermal gas jet probes, including post-plasma desorption/ionization sources, have not been studied using computational fluid dynamics (CFD) models, as have other ambient mass spectrometry sampling techniques. Two systems were constructed: a heated nitrogen jet probe to establish practical bounds for a sampling/transmission experiment and a CFD model to study trajectories of particles desorbed from a surface through optimization of streamlines and temperatures. The physical model configuration as tested using CFD revealed large losses, transmitting less than 10% of desorbed particles. Different distances between the desorption probe and the transport tube and from the sample surface were studied. The transmission improved when the system was very close to the sample, because the gas jet otherwise creates a region of low pressure that guides the streamlines below the inlet. A baffle positioned to increase pressure in the sample region improves collection efficiency. A Lagrangian particle tracking approach confirms the optimal design leading to a transmission of almost 100%.
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Affiliation(s)
- Xi Chen
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States.,Department of Mechanical Engineering, Purdue University, 610 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - G Asher Newsome
- Smithsonian Museum Conservation Institute, 4210 Silver Hill Rd., Suitland, Maryland 20746, United States
| | - Michael Buchanan
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States
| | - Jeremy Glasper
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States
| | - Leyan Hua
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States
| | - Mohsen Latif
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States
| | - Viraj Gandhi
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States.,Department of Mechanical Engineering, Purdue University, 610 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - Xintong Li
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States
| | - Carlos Larriba-Andaluz
- Department of Mechanical and Energy Engineering, IUPUI, 799 W. Michigan St., Indianapolis, Indiana 46202, United States
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3
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Molnar BT, Shelley JT. MODERN PLASMA-BASED DESORPTION/IONIZATION: FROM ATOMS AND MOLECULES TO CHEMICAL SYNTHESIS. MASS SPECTROMETRY REVIEWS 2021; 40:609-627. [PMID: 32770688 DOI: 10.1002/mas.21645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/05/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Since the first mass spectrometry (MS) experiments were conducted by Thomson and Aston, plasmas have been used as ionization sources. Historically, plasma ion sources were used for these experiments because they were one of the few known sources of gas-phase ions at the time and they were relatively simple to setup and operate. Since then, developments in plasma ionization have continued to inform and motivate advances in other areas of MS. For example, plasma-desorption MS demonstrated ionization of large peptides and polymers more than 10 years before the first descriptions of electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). As a result, significant effort was placed on development of ionization approaches, mass analysis, and detection approaches for very large molecules: even before the advent of ESI and MALDI. Since then, new analytical challenges and opportunities in plasma ionization have arisen. In this review, the emerging trends in plasma-based ionization for several areas of MS will be discussed, including molecular ionization, elemental ionization, hybrid elemental and molecular ion sources, and unique chemical transformations. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Brian T Molnar
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180
| | - Jacob T Shelley
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180
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Pu J, Dai J, He F, Zhu S, Zhao Z, Duan Y. Interpretation of Ionization Mechanism Responsible for Reagent Ion and Analyte Formation in Microwave-Induced Plasma Desorption Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:752-762. [PMID: 32003981 DOI: 10.1021/jasms.0c00027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ambient desorption/ionization (ADI) sources coupled to mass spectrometer have gained increasing interest in the field of analytical chemistry for its fast and direct analysis of samples. Among many ADI sources, plasma-based ADI sources are an important branch. Despite its extensive use in mass spectrometry analysis, the ionization mechanism of these sources still remain uncertain. The study on ionization mechanism is of great significance to optimize the design of ion sources and to improve ionization efficiency. In this study, targeted research on a better understanding of afterglow distance effects on ionization process was conducted. Based on the quantified signal expression of reagent ions in mass spectrum, the concept that optimal atmospheric analysis distance of plasma ADI source is defined for the first time. From the perspective of mutual restriction effect between atmospheric components, the formation progress of reagent ions was visually revealed in detail, which involved the initial step of forming precursor reagent ions, the clusters reaction for increasing production of reagent ions, and the matrix effect results in reagent ion depletion. The formation mechanism of reagent ions further clarified the explicit reason for abundant reagent ions generated at an optimal distance. Most importantly, the analyte analysis results verified the significant impact of appropriate distance on ionization efficiency in afterglow region. It was confirmed that the quantity and type of reagent ions intimately influenced the status of analyte ions in mass spectrum.
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Affiliation(s)
| | - Jianxiong Dai
- College of Chemistry and Material Science, Northwest University, Xi'an 710069, P.R. China
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5
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Ahmed E, Xiao D, Dumlao MC, Steel CC, Schmidtke LM, Fletcher J, Donald WA. Nanosecond Pulsed Dielectric Barrier Discharge Ionization Mass Spectrometry. Anal Chem 2020; 92:4468-4474. [PMID: 32083845 DOI: 10.1021/acs.analchem.9b05491] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dielectric barrier discharge ionization (DBDI) is an emerging technique for ionizing volatile molecules directly from complex mixtures for sensitive detection by mass spectrometry (MS). In conventional DBDI, a high frequency and high voltage waveform with pulse widths of ∼50 μs (and ∼50 μs between pulses) is applied across a dielectric barrier and a gas to generate "low temperature plasma." Although such a source has the advantages of being compact, economical, robust, and sensitive, background ions from the ambient environment can be formed in high abundances, which limits performance. Here, we demonstrate that high voltage pulse widths as narrow as 100 ns with a pulse-to-pulse delay of ∼900 μs can significantly reduce background chemical noise and increase ion signal. Compared to microsecond pulses, ∼800 ns pulses can be used to increase the signal-to-noise and signal-to-background chemical noise ratios in DBDI-MS by up to 172% and 1300% for six analytes, including dimethyl methylphosphonate (DMMP), 3-octanone, and perfluorooctanoic acid. Using nanosecond pulses, the detection limit for DMMP and PFOA in human blood plasma can be lowered by more than a factor of 2 in comparison to microsecond pulses. In "nanopulsed" plasma ionization, the extent of internal energy deposition is as low as or lower than in electrospray ionization and micropulsed plasma ionization based on thermometer ion measurements. Overall, nanosecond high-voltage pulsing can be used to significantly improve the performance of DBDI-MS and potentially other ion sources involving high voltage waveforms.
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Affiliation(s)
- Ezaz Ahmed
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
| | - Dan Xiao
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - Morphy C Dumlao
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia.,School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.,National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, New South Wales, Australia.,Australian Research Council Training Centre for Innovative Wine Production, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Christopher C Steel
- School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.,National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Leigh M Schmidtke
- School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.,National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, New South Wales, Australia.,Australian Research Council Training Centre for Innovative Wine Production, University of Adelaide, Glen Osmond, South Australia, Australia
| | - John Fletcher
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales, Australia
| | - William A Donald
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
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Vogel P, Marggraf U, Brandt S, García-Reyes JF, Franzke J. Analyte-Tailored Controlled Atmosphere Improves Dielectric Barrier Discharge Ionization Mass Spectrometry Performance. Anal Chem 2019; 91:3733-3739. [PMID: 30672695 DOI: 10.1021/acs.analchem.9b00112] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Plasma sources in atmospheric pressure soft-ionization mass spectrometry have gained significant interest in recent years. As many of these sources are used under ambient air conditions, their interaction with the surrounding atmosphere plays an important role in the ionization pathway. This study focuses on the interaction between the plasma source and the surrounding atmosphere by connecting the plasma source to the mass spectrometer using a 2 mm ID closed reactant capillary supplied by a reactant gas up to 500 mL per minute to gain a controlled atmosphere. Different reactant gases (Ar, He, O2, and N2) and reactant gas mixtures are tested with regard to the DBDI performance and then used to improve the ionization efficiency. Tailoring the controlled atmosphere for a certain analyte, for example, perfluorinated compounds, leads to significantly improved limits of detection up to 2 ppb.
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Affiliation(s)
- Pascal Vogel
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. , Bunsen-Kirchhoff-Straße 11 , 44139 Dortmund , Germany
| | - Ulrich Marggraf
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. , Bunsen-Kirchhoff-Straße 11 , 44139 Dortmund , Germany
| | - Sebastian Brandt
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. , Bunsen-Kirchhoff-Straße 11 , 44139 Dortmund , Germany
| | - Juan F García-Reyes
- Analytical Chemistry Research Group , University of Jaén , Campus Las Lagunillas , 23071 Jaén , Spain
| | - Joachim Franzke
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. , Bunsen-Kirchhoff-Straße 11 , 44139 Dortmund , Germany
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7
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Knapp CE, Metcalf EA, Mrig S, Sanchez‐Perez C, Douglas SP, Choquet P, Boscher ND. Precursors for Atmospheric Plasma-Enhanced Sintering: Low-Temperature Inkjet Printing of Conductive Copper. ChemistryOpen 2018; 7:850-857. [PMID: 30402374 PMCID: PMC6208189 DOI: 10.1002/open.201800131] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Indexed: 11/10/2022] Open
Abstract
Bidentate diamine and amino-alcohol ligands have been used to form solid, water-soluble, and air-stable monomeric copper complexes of the type [Cu(NH2CH2CH(R)Y)2(NO3)2] (1, R=H, Y=NH2; 2, R=H, Y=OH; 3, R=Me, Y=OH). The complexes were characterized by elemental analysis, mass spectrometry, infrared spectroscopy, thermal gravimetric analysis, and single-crystal X-ray diffraction. Irrespective of their decomposition temperature, precursors 1-3 yield highly conductive copper features [1.5×10-6 Ω m (±5×10-7 Ω m)] upon atmospheric-pressure plasma-enhanced sintering.
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Affiliation(s)
- Caroline E. Knapp
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Elizabeth A. Metcalf
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Shreya Mrig
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Clara Sanchez‐Perez
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Samuel. P. Douglas
- Department of ChemistryUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Patrick Choquet
- Department of Materials Research and TechnologyLuxembourg Institute of Science and Technology5 Avenue des Hauts-FourneauxEsch/Alzette4362Luxembourg
| | - Nicolas D. Boscher
- Department of Materials Research and TechnologyLuxembourg Institute of Science and Technology5 Avenue des Hauts-FourneauxEsch/Alzette4362Luxembourg
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8
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Badal SP, Ratcliff TD, You Y, Breneman CM, Shelley JT. Formation of Pyrylium from Aromatic Systems with a Helium:Oxygen Flowing Atmospheric Pressure Afterglow (FAPA) Plasma Source. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1013-1020. [PMID: 28361384 DOI: 10.1007/s13361-017-1625-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 02/06/2017] [Accepted: 02/07/2017] [Indexed: 06/07/2023]
Abstract
The effects of oxygen addition on a helium-based flowing atmospheric pressure afterglow (FAPA) ionization source are explored. Small amounts of oxygen doped into the helium discharge gas resulted in an increase in abundance of protonated water clusters by at least three times. A corresponding increase in protonated analyte signal was also observed for small polar analytes, such as methanol and acetone. Meanwhile, most other reagent ions (e.g., O2+·, NO+, etc.) significantly decrease in abundance with even 0.1% v/v oxygen in the discharge gas. Interestingly, when analytes that contained aromatic constituents were subjected to a He:O2-FAPA, a unique (M + 3)+ ion resulted, while molecular or protonated molecular ions were rarely detected. Exact-mass measurements revealed that these (M + 3)+ ions correspond to (M - CH + O)+, with the most likely structure being pyrylium. Presence of pyrylium-based ions was further confirmed by tandem mass spectrometry of the (M + 3)+ ion compared with that of a commercially available salt. Lastly, rapid and efficient production of pyrylium in the gas phase was used to convert benzene into pyridine. Though this pyrylium-formation reaction has not been shown before, the reaction is rapid and efficient. Potential reactant species, which could lead to pyrylium formation, were determined from reagent-ion mass spectra. Thermodynamic evaluation of reaction pathways was aided by calculation of the formation enthalpy for pyrylium, which was found to be 689.8 kJ/mol. Based on these results, we propose that this reaction is initiated by ionized ozone (O3+·), proceeds similarly to ozonolysis, and results in the neutral loss of the stable CHO2· radical. Graphical Abstract ᅟ.
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Affiliation(s)
- Sunil P Badal
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44240, USA
| | - Tyree D Ratcliff
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Yi You
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44240, USA
| | - Curt M Breneman
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Jacob T Shelley
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44240, USA.
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Martínez-Jarquín S, Winkler R. Low-temperature plasma (LTP) jets for mass spectrometry (MS): Ion processes, instrumental set-ups, and application examples. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.01.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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